The invention relates to a radio receiver having a decoder for decoding of traffic advisories received in digitally encoded form according to U.S. Pat. No. 4,862,513.
A decoder for traffic advisories adapted to process digital signals is known from German Unexamined Patent Disclosure DE-OS 35 36 820, BRAGAS AND BUSCH, published Apr. 16, 1987. The digital signals are obtained by demodulation of an auxiliary carrier which is broadcast by radio stations in conjunction with an FM radio program. Because this auxiliary carrier does not interfere with the normal radio program, it is possible to transmit digital signals with traffic advisories without interruption of the current radio program.
It has already been proposed in the cited reference to design standard texts in accordance with the formatting principle in which traffic advisories are put together and to store them in memories at the receiving end. It is then possible to read out the standard texts with the aid of the digital signals by addressing the memory places where they are stored and to display them accordingly, either acoustically or visually.
While a large amount of transmission capacity can be saved by storing standardized texts for factual information, this is not the case with numerical information. For this reason it had been provided to transmit factual information which also contained additional numerical values in such a way, that the numerical values are wholly transmitted in the respective transmission code and the remaining factual information only as addresses of memory fields or memory places in which texts are stored.
Because the digital transmission of traffic announcements allows frequent repetition or a large amount of traffic announcement transmissions, there is the possibility to transmit regional and super-regional traffic announcements via every transmitter of a transmitter network. However, because of the temporarily large amounts of traffic announcements during periods of high traffic, this may result in the repeat time intervals between repetitions becoming so long that timeliness can no longer be assured.
Furthermore, from the viewpoint of signal processing it is also very cumbersome to decode and process digital signals which have been cut up and distributed to several blocks within a transmission format.